Study of imaging changes following preoperative denosumab for giant cell tumor of bone

BACKGROUND: The changes in the characteristics of the tumor blood supply of giant cell tumor of bone over time after treatment with denosumab remain unclear. The purpose of this study was to evaluate the change in the blood supply imaging characteristics of giant cell tumor of bone after preoperative denosumab treatment and to provide evidence for evaluating the reasonable time for preoperative treatment. METHODS: A total of 59 patients with giant cell tumor of bone who were treated in our hospital from 2014 to 2019 were enrolled in the study. All patients underwent enhanced CT examination of the tumor site before denosumab treatment and every month after treatment. The plain CT value and enhanced CT value of the tumor were measured, and the CT enhancement rate of the tumor was calculated. The change in the CT enhancement rate of the tumor over time after denosumab treatment was analyzed. RESULTS: The average tumor enhancement rates were 2.14 (1.22–4.05), 1.60 (1.12–2.53), 1.38 (1.02–2.24), and 1.25 (1–2.11) before denosumab treatment and one month, three months, and six months after treatment, respectively. After denosumab treatment, the average monthly CT enhancement rate decreased as follows: 0.54 (25.2%) in the first month, 0.11 (5.15%) in the second to third months, and 0.04 (1.87%) in the fourth to sixth months. The tumor enhancement rate was no longer significantly reduced three months post-treatment. There was a significant correlation between the reduction in the CT enhancement rate and the initial CT enhancement rate (P = 0.000). CONCLUSION: The preoperative application of denosumab can reduce tumor blood supply. The decrease in the blood supply is the most significant in the initial stage of treatment. Following treatment, the decrease in the blood supply gradually reduces over time. Therefore, for the purpose of reducing intra-operative bleeding and facilitating surgery, application of denosumab treatment is not recommended more than three months before surgery.